package com.hmdp.service.impl;

import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.ShopType;
import com.hmdp.mapper.ShopTypeMapper;
import com.hmdp.service.IShopTypeService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

import java.util.List;

import static com.hmdp.utils.RedisConstants.CACHE_SHOP_TYPE_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopTypeServiceImpl extends ServiceImpl<ShopTypeMapper, ShopType> implements IShopTypeService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Override
    public Result show() {
        String key = CACHE_SHOP_TYPE_KEY;
        //1.从redis中查询
        String shopTypeJson = stringRedisTemplate.opsForValue().get(key);
        //2.若存在，直接返回缓存信息
        if (StrUtil.isNotBlank(shopTypeJson)) {
            List<ShopType> shopType = JSONUtil.toList(shopTypeJson, ShopType.class);
            return Result.ok(shopType);
        }
        //3.若不存在，查询数据库
        List<ShopType> shopType = query().orderByAsc("sort").list();
        //4.若数据库中不存在，返回错误信息
        if (shopType.isEmpty()) {
            return Result.fail("暂无商铺信息");
        }
        //5.若数据库中存在，写入缓存
        stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shopType));
        //6.返回数据
        return Result.ok(shopType);
    }
}
